The use of liquid desiccants for dehumidification of air has been known for well over 75 years. The application of liquid desiccants in dehumidification in heating, ventilating, and air conditioning (HVAC) systems has been worked on for many years. Open absorption systems for air conditioning are desirable due to their relatively simple design and driving energy at relatively low temperatures. Liquid desiccant air conditioning (LDAC) is an exemplary open absorption system.
Heat and mass exchange (HMX) modules have been researched and attempted for use in LDAC systems. Some module designs incorporated three fluid paths: one for desiccant, one for air, and one for coolant; and other designs incorporate two fluid paths: one for desiccant and one for air. Certain designs have provided benefits on the performance of the absorber side of the system but not on the desorber side, and overall commercial success of liquid desiccant air conditioning (LDAC) systems has been extremely limited.
U.S. Pat. No. 7,269,966 (Lowenstein) discloses a heat and mass exchange assembly having a wettable substrate positioned in spaces between adjacent plates and in contact with adjacent plates in a plurality of locations along with a liquid supply assembly, which delivers the liquid from a source to upper regions of the plates.